排序方式： 共有32条查询结果，搜索用时 46 毫秒
31.
本研究采用了一种新的元素检测方法,即用X射线分析显微镜来引导分离羊栖菜(Sargassum fusiformis)中有机溴化合物。新鲜羊栖菜经提取、浓缩、洗脱等处理,所得洗脱液经冷冻干燥后,用X射线分析显微镜分析其元素组成。X射线荧光光谱得到的结果表明,这种检测方法十分有效,能够证实有机溴化合物在PVPP柱色谱中得到了有效的浓缩与分离。MALDI-TOFMS质谱显示存在两个有机溴化合物,分子量分别为330和554,质谱的同位素特征表明,每个有机溴化合物分子中分别含有一个溴原子。该有机溴化物具有以下的化学特征:水溶性较强,能够被PVPP柱吸附,而在弱碱条件下溶出;在水溶液中不太稳定,容易形成沉淀。该有机溴化物的紫外可见光谱特征具有多酚化合物的特点,并与海藻中的砷化物具有某种程度的相互作用。 相似文献
32.
Thomas Hobiger Tadahiro Gotoh Jun Amagai Yasuhiro Koyama Tetsuro Kondo 《GPS Solutions》2010,14(2):207-216
Off-the-shelf graphics processing units provide low-cost massive parallel computing performance, which can be utilized for
the implementation of a GPS software receiver. In order to realize a real-time capable system the crucial stages of the receiver
should be optimized to suit the requirements of a parallel processor. Moreover, the receiver should be capable to provide
wider correlation functions and provide easy access to the spectral domain of the signals. Thus, the most suitable correlation
algorithm, which forms the core part of each receivers should be chosen and implemented on the graphics processor. Since the
sampling rate of the received signal limits the real-time capabilities of the software radio it is necessary to determine
an optimum value, considering that the precision of the observable varies with sampling bandwidth. We are going to discuss
details and present our single frequency multi-channel implementation, which is capable of operating in real-time mode. Our
implementation differs from other solutions by the wideness of the correlation function and allows simple handling of data
in the spectral domain. Comparison with output from a commercial hardware receiver, which shares the antenna with the software
radio, confirms the consistency and accuracy of our development. 相似文献